Region 4 U.S. Environmental Protection Agency Science and Ecosystem Support Division Athens, Georgia OPERATING PROCEDURE Title: Effective Date: September 8, 2010 Number: SESDPROC-200-R2 Authors Name: Kevin Simmons Title: ental Sc. ientist, Regional Expert Signature: :t-<."' Date: Approvals Name: Archie Lee Title: Chief, Enforcement and Investigations Branch Name: ill Cosgrove Title: Chief, E logical Assessment Branch Signature: Date: 9 Name: Liza ontalvo JO Title: Field Quality Manager, Science a d Ecosystem Support Division Signature: SESD Operating Procedure Sediment Sampling Effective Date: September 8, 2010 Date: Page 1 of23 SESDPROC-200-R2 Sediment Sampling(200)_AF.R2
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COPY - epa.gov · COPY 1. 5.2 Procedural Precautions The following precautions should be considered when collecting sediment samples. • Special care must be taken not to contaminate
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COPYCOPYRegion 4
U.S. Environmental Protection Agency Science and Ecosystem Support Division
Athens, Georgia
OPERATING PROCEDURE
Title:
Effective Date: September 8, 2010 Number: SESDPROC-200-R2
This table shows changes to this controlled document over time. The most recent version is presented in the top row of the table. Previous versions of the document are maintained by the SESD Document Control Coordinator.
History Effective Date
SESDPROC-200-R2, SESDPROC-200-R1.
Sediment Sampling, replaces September 8, 2010
Cover Page: The Enforcement and Investigations Branch Chief was changed from Antonio Quinones to Archie Lee. The FQM was changed from Laura Ackerman to Liza Montalvo.
Revision History: Changed Field Quality Manager to Document Control Coordinator.
Section 1.2: Added the following statement: "Mention of trade names or commercial products does not constitute endorsement or recommendation for use.''
Section 1.3: Omitted reference to the H: drive of the LAN. Changed Field Quality Manager to Document Control Coordinator.
SESDPROC-200-R1, SESDPROC-200-RO.
Sediment Sampling, replaces November 1, 2007
General Corrected any typographical, grammatical and! or editorial enors.
Title Page Changed title for Antonio Quinones from Environmental Investigations Branch to Enforcement and Investigations Branch. Changed Bill Cosgrove's title from Acting Chief to Chief.
Section 1.3 Updated infmn1ation to reflect that the procedure is located on the H: drive of the LAN. Clarified Field Quality Manager (FQM) responsibilities.
Section 1.4 Updated referenced operating procedures due to changes in title names. Alphabetized and revised the referencing style for consistency.
Section 1.5.1 Corrected the title of the Safety, Health, and Environmental Management Program Procedures and Policy Manual.
Equipment ................................................................................................... 9 Sampling Methodology- Low Concentrations ........................................ ! 0 Sampling Methodology- High Concentrations ....................................... IO Special Techniques and Considerations for Method 5035 ..................... !!
Special Precautions for Trace Contaminant Sediment Sampling ............... 13 Sample Homogenization ................................................................................. 14 Quality Control ................................................................................................ 15 Records ............................................................................................................. 15
3 General Considerations ........................................................................................... 16
3.1 General ............................................................................................................. 16 3.2 Equipment Selection Considerations ............................................................. 16
4 Stainless Steel Scoops and Spoons .......................................................................... 17
This document describes general and specific procedures, methods and considerations to be used and observed when collecting sediment samples for field screening or laboratory analysis.
1.2 Scope/ Application
The procedures contained in this document are to be used by field investigators when collecting and handling sediment samples in the field. On the occasion that SESD field investigators determine that any of the procedures described in this section are inappropriate, inadequate or impractical and that another procedure must be used to obtain a sediment sample, the variant procedure will be documented in the field log book, along with a desctiption of the circumstances requiring its use. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
1.3 DocumentationN erification
This procedure was prepared by persons deemed technically competent by SESD management, based on their knowledge, skills and abilities and has been tested in practice and reviewed in print by a subject matter expert. The official copy of this procedure resides on the SESD local area network (LAN). The Document Control Coordinator (DCC) is responsible for ensming the most recent version of the procedure is placed on the LAN and for maintaining records of review conducted prior to its issuance.
1.4 References
International Air Transport Authority (lATA). Dangerous Goods Regulations, Most Recent Version
SESD Operating Procedure for Control of Records, SESDPROC-004, Most Recent Version
SESD Operating Procedure for Sample and Evidence Management, SESDPROC-005, Most Recent Version
SESD Operating Procedure for Logbooks, SESDPROC-01 0, Most Recent Version
SESD Operating Procedure for Field Sampling Quality Control, SESDPROC-011, Most Recent Version
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
Page 6 of 23 SESDPROC-200-R2 Sediment Sampling(200)_AF.R2
COPYCOPYSESD Operating Procedure for Equipment Inventory and Management, SESDPROC-104,
Most Recent Version
SESD Operating Procedure for Field Equipment Cleaning and Decontamination, SESDPROC-205, Most Recent Version
SESD Operating Procedure for Field Equipment Cleaning and Decontamination at the
FEC, SESDPROC-206, Most Recent Version
SESD Operating Procedure for Packaging, Marking, Labeling and Shipping of
Environmental and Waste Samples, SESDPROC-209, Most Recent Version
Title 49 Code of Federal Regulations, Pts. 171 to 179, Most Recent Version
United States Environmental Protection Agency (US EPA). 2001. Enviromnental
Investigations Standard Operating Procedures and Quality Assurance Manual. Region 4 Science and Ecosystem Suppmi Division (SESD), Athens, GA
US EPA. Analytical Support Branch Laboratory Operations and Quality Assurance
Manual. Region 4 SESD, Athens, GA, Most Recent Version
US EPA. Safety, Health and Environmental Management Program Procedures and Policy Manual. Region 4 SESD, Athens, GA, Most Recent Version
United States Office of Occupational Health and Safety (US OSHA). 1981. Final Regulation Package for Compliance with DOT Regulations in the Shipment of
Environmental Laboratory Samples (PM-273), Memo from David Weitzman, Work Group Chairman, US EPA. April13, 1981.
1.5 General Precautions
1.5.1 Safety
Proper safety precautions must be observed when collecting sediment samples. Refer to the SESD Safety, Health and Environmental Management Program
(SHEMP) Procedures and Policy Manual and any pertinent site-specific Health and Safety Plans (HASPs) for guidelines on safety precautions. These guidelines should be used to complement the judgment of an experienced professional.
Address chemicals that pose specific toxicity or safety concerns and follow any other relevant requirements, as appropriate.
The following precautions should be considered when collecting sediment samples.
• Special care must be taken not to contaminate samples. This includes storing samples in a secure location to preclude conditions which could alter the properties of the sample. Samples shall be custody sealed dming long-tenn storage or shipment.
• Collected samples are in the custody of the sampler or sample custodian until the samples are relinquished to another party.
• If samples are transported by the sampler, they will remain under his/her custody or be secured until they are relinquished.
• Shipped samples shall conform to all U.S. Department of Transportation (DOT) rules of shipment found in Title 49 of the Code of Federal Regulations (49 CFR parts 171 to 179), and/or International Air Transportation Association (lATA) hazardous materials shipping requirements found in the cun·ent edition of lATA's Dangerous Goods Regulations.
• Documentation of field sampling is done in a bound logbook. • Chain-of-custody documents shall be filled out and remain with the
samples until custody is relinquished. • All shipping documents, such as air bills, bills of lading, etc., shall be
retained by the project leader and stored in a secure place.
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
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COPYCOPY2 Special Sampling Considerations
2.1 Sediment Samples for Volatile Organic Compounds Analysis
If samples are to be analyzed for volatile organic compounds (VOCs), they should be
collected in a mmmer that minimizes disturbance of the sample. The sample for VOC
analysis should be collected directly from the sample device, if possible, before it is
emptied into the pan. It may not be possible to do this with certain types of sediment
sampling equipment, such as the Ponar dredge. In cases such as these, the VOC aliquots
should be collected from the dredge contents immediately after they have been deposited
in the pan and ptior to any mixing. The sample shall be placed in the appropriate
container (En Core® Sampler or other Method 5035 compatible container) with no
headspace. Samples for VOC analysis are not homogenized. Preservatives may be
required for some samples with certain variations of Method 5035. Consult the method
description below in Section 2.2, Sediment Sampling (Method 5035) or the principal
analytical chemist to determine if preservatives are necessary.
In some cases, the sediment may be soft and not lend itself to collection by plunging En
Core® Samplers or syringe samplers into the sample mallix. In these cases, it is
appropriate to open the sample device, i.e., the En Core® Sampler barrel or syringe, ptior
to sample collection, and to carefully place the sediment in the device, filling it fully with
the required volume of sample.
2.2 Sediment Sampling (Method 5035)
The following sampling protocol is recommended for site investigators assessing the
extent of VOCs in sediments at a project site. Because of the large number of options
available, careful coordination between field and laboratory personnel is needed. The
specific sampling containers and sampling tools required will depend upon the detection
levels and intended data use. Once this information has been established, selection of the
appropriate sampling procedure and preservation method best applicable to the
investigation can be made.
· 2.2.1 Equipment
Sediment for VOC analyses may be retrieved using any of the SESD sediment
sampling methods described in Sections 3 through 6 of this procedure. Once the
sediment has been .obtained, the En Core® Smupler, syringes, stainless steel
spatula, standard 2-oz. sediment VOC container, or pre-prepared 40 ml vials may
be used/required for sub-sampling. The specific sample containers and the
sampling tools required will depend upon the data quality objectives established
for the site or sampling investigation. The various sub-sampling methods are
described below.
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
Page 9 of 23 SESDPROC-200-R2 Sediment Sampling(200)_AF.R2
When the total VOC concentration in the sediment is expected to be less than 200 >tg/kg, the samples may be collected directly with the En Core® Sampler or sytinge. If using the syringes, the sample must be placed in the sample container ( 40 ml pre-prepared vial) immediately to reduce volatilization losses. The 40 ml vials should contain l 0 ml of organic-fi·ee water for an un-preserved sample or approximately 10 ml of organic-free water and a preservative. It is recommended that the 40 ml vials be prepared and weighed by the laboratory (commercial sources are available which supply preserved and tared vials). When sampling directly with the En Core® Sampler, the vial must be immediately capped and locked.
A sediment sample for VOC analysis may also be collected with conventional sampling equipment. A sample collected in this fashion must either be placed in the final sample container (En Core® Sampler or 40 ml pre-prepared vial) immediately or the sample may be immediately placed into an intennediate sample container with no head space. If an intermediate container (usually 2-oz. sediment jar) is used, the sample must be transfelTed to the final sample container (En Core® Sampler or 40 ml pre-prepared vial) as soon as possible, not to exceed 30 minutes.
NOTE: After collection of the sample into either the En Core® Sampler or other container, the sample must immediately be stored in an ice chest and cooled.
Sediment samples may be prepared for shipping and analysis as follows:
En Core® Sampler - the sample shall be capped, locked, and secured in a plastic bag.
Syringe- Add about 3.7 cc (approximately 5 grams) of sample material to 40-ml pre-prepared containers. Secure the containers in a plastic bag. Do not use a custody seal on the container; place the custody seal on the plastic bag. Note: When using the syringes, it is important that no air is allowed to become trapped behind the sample prior to extrusion, as this will adversely affect the sample.
Stainless Steel Laborat01y Spatulas - Add between 4.5 and 5.5 grams (approximate) of sample material to 40 ml containers. Secure the containers in a plastic bag. Do not use a custody seal on the container; place the custody seal on the plastic bag.
2.2.3 Sampling Methodology- High Concentrations
Based upon the data quality objectives and the detection level requirements, this high level method may also be used. Specifically, the sample may be packed into
COPYCOPYa single 2-oz. glass container with a screw cap and septum seal. The sample container must be filled quickly and completely to eliminate head space. Sediments containing high total VOC concentrations may also be collected as described in Section 2.2.2, Sampling Methodology - Low Concentrations, and preserved using I 0 ml methanol.
2.2.4 Special Techniques and Considerations for Method 5035
Effervescence
If low concentration samples effervesce from contact with the acid preservative, then either a test for effervescence must be performed prior to sampling, or the investigators must be prepared to collect each sample both preserved or unpreserved as needed, or all samples must be collected unpreserved.
To check for effervescence, collect a test sample and add to a pre-preserved vial. If preservation (acidification) of the sample results in effervescence (rapid formation of bubbles) then preservation by acidification is not acceptable, and the sample must be collected un-preserved.
If effervescence occurs and only pre-preserved sample vials are available, the preservative solution may placed into an approptiate hazardous waste container and the vials triple rinsed with organic-free water. An appropriate amount of organic-free water, equal to the amount of preservative solution, should be placed into the vial. The sample may then be collected as an un-preserved sample. Note that the amount of organic free water placed into the vials will have to be accurately measured.
Sample Size
While this method is an improvement over earlier ones, field investigators must be aware of an inherent limitation. Because of the extremely small sample size, sample representativeness for VOCs may be reduced compared to samples with larger volumes collected for other constituents. The sampling design and objectives of the investigation should take this into consideration.
Holding Times
Sample holding times are specified in the USEP A Region 4 Analytical Suppmi Branch Laboratory Operations and Quality Assurance Manual (ASBLOQAM), Most Recent Version. Field investigators should note that the holding time for an un-preserved VOC sediment sample is 48 hours. AtTangements should be made to ship the sediment VOC samples to the laboratory by overnight delivery the day they are collected so the laboratory may preserve and/or analyze the sample within 48 hours of collection.
Samplers must ensure that the laboratory has sufficient material to detennine percent moisture in the VOC sediment sample to correct the analytical results to dry weight. If other analyses requiring percent moisture detennination are being performed upon the sample, these results may be used. If not, a separate sample (minimum of2 oz.) for percent moisture determination will be required.
Methanol is a toxic and flammable liquid. Therefore, methanol must be handled with all required safety precautions related to toxic and flammable liquids. Inhalation of methanol vapors must be avoided. Vials should be opened and closed quickly during the sample preservation procedure. Methanol must be handled in a ventilated area. Use protective gloves when handling the methanol vials. Store methanol away fi·om sources of ignition such as extreme heat or open flames. The vials of methanol should be stored in a cooler with ice at all times.
Shipping
Methanol and sodium bisulfate are considered dangerous goods, therefore shipment of samples preserved with these materials by common carrier is regulated by the U.S. Department of Transportation and the International Air Transport Association (lATA). The rules of shipment found in Title 49 of the Code of Federal Regulations (49 CFR parts 171 to 179) and the cutTent edition of the lATA Dangerous Goods Regulations must be followed when shipping methanol and sodium bisulfate. Consult the above documents or the carrier for additional information. Shipment of the quantities of methanol and sodium bisulfate used for sample preservation falls under the exemption for small quantities. A summary of the requirements for shipping samples follows. Refer to the code for a complete review of the requirements.
1. The maximum volume of methanol or sodium bisulfate in a sample container is limited to thirty (30) mi.
2. The sample container must not be full of methanol.
3. The sample container must be stored uptight and have the lid held securely in place. Note that the mechanism used to hold the cap in place must be able to be completely removed so weight is not added to the sample container, as specified in Method 503 5.
4. Sample containers must be packed in an absorbent material capable of absorbing spills fi·omleaks or breakage of the sample containers.
COPYCOPY5. The maximum sample shuttle weight must not exceed 64 pounds.
6 The maximum volume of methanol or sodium bisulfate per shipping container is 500 mi.
7 The shipper must mark the sample shuttle m accordance with shipping dangerous goods in acceptable quantities.
8. The package must not be opened or altered until no longer in commerce.
The following summary table lists the options available for compliance with
SW846 Method 5035. The advantages and disadvantages are noted for each option. SESD's goal is to minimize the use of hazardous matetial (methanol and
sodium bisulfate) and minimize the generation of hazardous waste during sample collection.
OPTION PROCEDURE ADVANTAGES DISADVANTAGES
1 Collect 2- 40 ml vials with -5 Screening conducted by Presently a 48 hour grams of sample and 1 - 2 oz. lab holding time for glass w/septum lid for unpreserved samples screening and % moisture
2 Collect 3 EnCore® Samplers Lab conducts all Presently a 48 hour and 1 - 2oz. g;lass w/septum preservation/preparation holding time for lid for screemng and procedures preparation of samples %moisture
3 Collect 2 - 40 ml vials with High level VOC Hazardous matetials 5 grams of samhle and samples may be used in field preserve w/met 1anol or composited sodium bisulfate, and 1 - 2 oz. glass w/septum lid for screening and %moisture Longer holding time
4 Collect 1 - 2 oz. glass Lab conducts all May have significant w/septum lid for analysis and preservatiottlpreparation VOC loss %moisture procedures
2.3 Special Precautions for Trace Contaminant Sediment Sampling
• A clean pair of new, non-powdered, disposable gloves will be worn each time a different location is sampled and the gloves should be donned immediately ptior to sampling. The gloves should not come in contact with the media being sampled and should be changed any time during sample collection when their cleanliness is compromised.
• Sample containers for samples suspected of containing high concentrations of contaminants shall be stored separately. All background
COPYCOPYsamples shall be collected and placed in separate ice chests or shipping containers. Sample collection activities shall proceed progressively from the least suspected contaminated area to the most suspected contaminated area if sampling devices are to be reused. Samples of waste or highly contaminated media must not be placed in the same ice chest as environmental (i.e., containing low contaminant levels) or background samples.
• If possible, one member of the field sampling team should take all the notes and photographs, fill out tags, etc., while the other members collect the samples.
• Samplers must use new, verified and certified-clean disposable or nondisposable equipment cleaned according to procedures contained in SESD Operating Procedure for Field Equipment Cleaning and Decontamination, SESDPROC-205, or SESD Operating Procedure for Field Cleaning and Decontamination at the FEC, SESDPROC-206, for collection of samples for trace metals or organic compound analyses.
2.4 Sample Homogenization
I. If sub-sampling of the primary sample is to be performed in the laboratory, transfer the entire primary sample directly into an approptiate, labeled sample container(s). Proceed to step 5
2. If sub-sampling the primary sample in the field or compositing multiple primary samples in the field, place the sample into a glass or stainless steel homogenization container and mix thoroughly. Each aliquot of a composite sample should be of the same volume.
3. All sediment samples must be thoroughly mixed to ensure that the sample is as representative as possible of the sample media. Samples for VOC analysis are not homogenized. The most common method of mixing is refen·ed to as qum1ering. The quartering procedure should be perf01med as follows:
• The material in the sample pan should be divided into quarters and each quarter should be mixed individually.
• Two qum1ers should then be mixed to fonn halves. • The two halves should be mixed to form a homogenous matlix.
This procedure should be repeated several times until the sample is adequately mixed. If round bowls are used for sample mixing, adequate mixing is achieved by stining the material in a circular fashion, reversing direction, and occasionally tuming the material over.
COPYCOPY3. Place the sample into an appropriate, labeled container(s) using the alternate
shoveling method and secure the cap(s) tightly. Tlu·eads on the container and lid
should be cleaned to ensure a tight seal when closed.
4. Return any unused sample material back to the location from which the sample
was collected.
2.5 Quality Control
If possible, a control sample should be collected from an area not affected by the possible
contaminants of concern and submitted with the other samples. The control sample
should be collected at an upstream location in the same stream or conveyance from which
the primary samples area collected. Equipment blanks should be collected if equipment
is field cleaned and re-used on-site or if necessary to document that low-level
contaminants were not introduced by sampling tools.
2.6 Records
lnfonnation generated or obtained by SESD personnel will be organized and accounted
for in accordance with SESD records management procedures found in SESD Operating
Procedure for Control of Records, SESDPROC-004. Field notes, recorded in a bound
field logbook, will be generated, as well as chain-of-custody documentation in
accordance with SESD Operating Procedure for Logbooks, SESDPROC-010 and SESD
Procedure for Sample and Evidence Management, SESDPROC-005.
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
Page 15 of 23 SESDPROC-200-R2 Sediment Sampling(200LAF.R2
COPYCOPY3 General Considerations
3.1 General
The sediment sampling techniques and equipment described in the following Sections 4, 5 and 6 of this procedure document are designed to minimize effects on the chemical and physical integrity of the sample. If the procedures in this section are followed, a representative sample of the sediment should be obtained.
3.2 Equipment Selection Considerations
The physical location of the investigator when collecting a sample may dictate the equipment to be used. Wading is the preferred method for reaching the sampling location, particularly if the stream has a noticeable cun·ent (is not impounded). However, wading may disrupt bottom sediments causing biased results; therefore, the samples should be collected facing upstream. If the stream is too deep to wade, the sediment sample may be collected from a platfonn such as a boat or a bridge.
To collect a sediment sample from a water body or other surface water conveyance, a vmiety of methods can be used:
Regardless of the method used, precautions should be taken to insure that the sample collected is representative of the water body or conveyance. These methods are discussed in the following paragraphs.
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
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COPYCOPY4 Stainless Steel Scoops and Spoons
4.1 Wading
If the conveyance is dry or is a wadeable surface water body, the easiest way to collect a sediment sample is by using a stainless steel scoop or spoon. If the conveyance is dry, the sediment is accessed directly and is collected using either the stainless steel scoop or spoon. If the conveyance is a wadeable stream or other water body, the method is accomplished by wading into the surface water body and while facing upstream (into the current), scooping the sample along the bottom of the surface water body in the upstream direction. Excess water may be removed/drained from the scoop or spoon. However, this may result in the loss of some fine-grained particle size matetial associated with the substrate being sampled. Care should be taken to minimize the loss of this fine-grained material. Aliquots of the sample thus collected are then placed in a glass pan and homogenized according to the quartering method described in Section 2.4.
4.2 Bank/Platform Sampling
In surface water bodies that are too deep to wade, but less than eight feet deep, a stainless steel scoop or spoon attached to a piece of conduit can be used either from the banks, if the surface water body is nmrow, or from a boat. Again, care should be taken to minimize the loss of the fine pmiicle sizes. The sediment is placed into a glass pan arid mixed according to the quartering method described in Section 2.4.
Dredges provide a means of collecting sediment from surface water bodies that are too deep to access with a scoop and conduit. They are most useful when collecting softer, finer-grained substrates comprised of silts and clays but can also be used to collect sediments comprised of sands and gravel, although sample recove1y in these materials may be less than complete.
Free, vertical clearance is required to use any of the dredges. Dredges, attached to ropes, are lowered vertically from the sampling platform (boat, bridge, etc.) to the substrate being sampled beneath the deployment point.
5.2 Ponar Dredge
The Ponar dredge has side plates and a screen on the top of the sample compartment and samples a 0.05 nl surface area. The screen over the sample compartment permits water to pass through the sampler as it descends thus reducing turbulence around the dredge. The Ponar dredge is easily operated by one person and is one of the most effective samplers for general use on most types of substrates.
The Ponar dredge is deployed in its open configuration. It is lowered gently fi·om the sampling platform to the substrate below the platfonn. After the dredge lands on the substrate, the rope is tugged upward, closing the dredge and captming the sample. The dredge is then hauled to the surface, where it is opened to acquire the sample.
5.3 Mini-Ponar Dredge
The Mini-Ponar dredge is a smaller, much lighter version of the Ponar dredge and samples a 0.023 m2 surface area. It is used to collect smaller sample volumes when working in industrial tanks, lagoons, ponds, and shallow water bodies. It is a good device to use when collecting sludge and sediment containing hazardous constituents because the size of the dredge makes it more amenable to field cleaning. Its· use and operation are the same as described in Section 5.2, Ponar Dredge, above.
5.4 Young Grab
The Young grab sampler is a stainless steel clamshell-type grab sampler similar to a Ponar dredge. It is a clamshell-type sampler with a scissors closing action typically used for marine and estuarine sediment sampling. TheY oung grab sampler is one of the most consistently performing grab sampling devices for sediment sampling in both offshore mmine sediments, as well as estuarine sediments. The Young sampler comes in two sizes, 0.1 m2 and 0.04 m2 The 0.1 m2 is typically used when a larger volume of sediment is needed for chemistry and particle size. The 0.04 m2 is typically used for marine
Core samplers are used to sample vertical columns of sediment. They are particularly useful when a historical picture of sediment deposition is desired since they preserve the sequential layering of the deposit. They are also particularly useful when it is desirable to minimize the loss of material at the sediment-water interface. Many types of coring devices have been developed, depending on the depth of water from which the sample is to be obtained, the nature of the bottom mate1ial and the length of core to be collected. They vary from hand-driven push tubes to electronic vibrational core tube drivers. These methods are described below in the following sections.
Coring devices are particularly useful in pollutant monitming because turbulence created by descent through the water is minimal, thus the fines at the sediment-water interface are only minimally disturbed; the sample is withdrawn intact, pennitting the removal of only those layers of interest; core liners manufactured of glass or Teflon® can be purchased, thus reducing possible sample interferences; and the samples are easily delivered to the lab for analysis in the tube in which they were collected.
The disadvantage of coring devices is that a relatively small surface area and sample size is obtained, often necessitating repetitive sampling in order to obtain the required amount of material for analysis. Because it is believed that this disadvantage is offset by the advantages, coring devices are recommended in sampling sediments for trace organic compounds or metals analyses.
6.2 Manually Deployed Push Tubes
In shallow, wadeable waters, or for diver-collected samples, the direct use of a core liner or tube manufactured of Teflon®, plastic, or glass is recommended for the collection of sediment samples. Plastic tubes are principally used for collection of samples for physical parameters such as particle size analysis and, in some instances, are acceptable when inorganic constituents are the only parameter of concern. Their use can also be extended to deep waters when SCUBA diving equipment is utilized. Teflon® or plastic is preferred to glass since they are unbreakable, reducing the possibility of sample loss or personal injury. Stainless steel push tubes are also acceptable and provide a better cutting edge and higher strength than Teflon®. The use of glass or Teflon® tubes eliminates any possible interference due to metals contamination from core barrels, cutting heads, and retainers. The tube should be approximately 12-inches in length if only recently deposited sediments (8 inches or less) are to be sampled. Longer tubes should be used when the depth of the substrate exceeds 8 inches. Soft or semi-consolidated sediments such as mud and clays have a greater adherence to the inside of the tube and thus can be sampled with larger diameter tubes. Because coarse or unconsolidated sediments, such as sands and gravel, tend to fall out of the tube, a smaller diameter push h1be is nmmally required to obtain a sample. In extreme cases, where sample retention in the tube is
SESD Operating Procedure Sediment Sampling
Effective Date: September 8, 2010
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COPYCOPYproblematic, core-catchers or end caps made of Teflon® should be employed. A tube about two-inches in diameter is usually the best size. The wall thickness of the tube should be about 1/3-inch for Teflon® plastic, or glass. The inside wall may be filed down at the bottom of the tube to provide a cutting edge to facilitate entry of the liner into
the substrate.
Caution should be exercised not to disturb the bottom sediments when the sample is obtained by wading in shallow water (always work facing upstream and working fiom downstream up). The core tube is pushed into the substrate until four inches or less of the
tube is above the sediment-water interface. When sampling hard or coarse substrates, a gentle rotation of the tube while it is being pushed will facilitate greater penetration and
decrease core compaction. The top of the tube is then capped to provide suction and reduce the chance of losing the sample. A Teflon® plug or end cap, or a sheet of Teflon® held in place by a rubber stopper or cork may be used. After capping, the tube
is slowly extracted with the suction and adherence of the sediment keeping the sample in the tube. Before pulling the bottom part of the tube and core above the water surface, it too should be capped. An alternative to the coring device is the Shelby tube. The Shelby tube has a gravity check valve at the top of the tube where an auger handle attaches. This
check valve allows air and water to escape as the tube is advanced. Once the tube is to the desired depth, the check valve will close automatically forming suction on the tube;
thus, holding the sample inside.
When extensive core sampling is required, such as a cross-sectional examination of a
streambed with the objective of profiling both the physical and chemical contents of the sediment, complete cores are desirable. A strong coring tube such as one made fi·om
aluminum, steel or stainless steel is needed to penetrate the sediment and underlying clay or sands. To facilitate complete core collection and retention, it is recommended that the corer (like a Shelby tube) have a check valve built into the driving head which allows water and air to escape from the cutting core, thus creating a pmiial vacuum, helping to
hold the sediment core in the tube. The corer is attached to a standard auger extension and handle, allowing it to be corkscrewed into the sediment from a boat or while wading. The coring tube is easily detached and the intact sediment core is removed with an
extraction device.
Before extracting the sediment from the coring tubes, the clear supernatant above the sediment-water interface in the core should be decanted from the tube. This is accomplished by simply turning the core tube to its side, and gently pouring the liquid out
until fine sediment pmiicles appear in the waste liquid. The loss of some of the fine sediments usually occurs with this technique.
6.3 Ogeechce Sand Pounders® and Gravity Cores
In deeper, non-wadeable water bodies, sediment cores may be collected fi·om a bridge or a boat using different coring devices such as Ogeechee Sand Pounders®, gravity cores and vibrating coring devices. All three devices utilize a core ban·el with a core liner tube
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Effective Date: September 8, 2010
Page 21 of 23 SESDPROC-200-R2 Sediment Sampling(200)_AF.R2
COPYCOPYsystem. The core liner can be removed from the core barrel and replaced with a clean core liner, as needed, after each sample. Liners are made of stainless steel, Teflon® or plastic. The type of core liner and its composition should be based on the contaminants to be evaluated.
Ogeechee Sand Pounders® and gravity cores are hand-held devices that use a standard size 2-inch diameter core barrel. The core tube and liner are interchangeable between the two units. The Ogeechee® uses a slide-hammer mechanism attached to the core head that allows the sampler to pound the core tube into the sediment. The Ogeechee® is good for sandy, more consolidated sediments. The gravity core uses a guiding fin mechanism with a built-in gravity-type check valve. The gravity core is placed in the water and released at the surface to free fall to the bottom. The fin mechanism keeps the core tube uptight and free from spinning in the water column as it descends. The core tube stabs the bottom, forcing the sediment into the tube. Both coring devices are equipped with removable nose pieces on the core barrel and disposable core catchers for the liner tubes. The core catchers are designed to cap the liner tube to avoid loss of the core when retrieved from the bottom. The gravity core can be modified to attach a slide hammer mechanism, similar to the Ogeechee®, to further pound the core into the sediment further if deemed necessary.
Sediment cores collected from most hand operated coring devices can suffer from either spreading or compaction when driven into the sediment, depending on the softness of the sediment. Spreading occurs when the sediment is pushed or moved to the side dming the advancement of the core tube. Compaction occurs when the sediment is being pushed downward as the core tube is advanced. Both phenomena can affect the physical integrity of the core sample. For instance, the core tube may be advanced through the sediment to a depth of 3 6 inches, but upon examination of the recovered core, there is only 24 inches of sediment in the core tube.
6.4 Vibratory Core Tube Drivers (Vibracore®)
Vibratory Core Tube Drivers (Vibracore®) facilitate sampling of soft or loosely consolidated, saturated sediments, with minimal compaction or spreading, using lined or unlined core tubes. It is designed for use- with core tubes having nominal diameters ranging from 2-inches to 4-inches OD. The Vibracore® uses an electric motor to create vibration ranges from approximately 6,000 RPM to 8,000 RPM (I 00 Hz to 133 Hz) depending on the resistance afforded by the sediment; the greater the resistance, the higher the frequency. The actual vibrational displacement of the Vibracore® is on the order of a few tens of thousandths of an inch, so essentially no mixing of the sediment within the htbe occurs. The vibrational energy tends to re-mient the sediment particles at the lower end of the core tube, causing them to move out of the way of the advancing wall of the core tube and into a more efficient (i.e. denser) packing. This action advances the core tube with minimal compaction of the sediment.
Sediment samples can also be obtained from large streams and open water bodies such as ponds, lakes, estuarine bodies and open ocean environments by divers. Using a variety of the above mentioned methods, divers can directly access the substrate and collect sediment samples. Depending upon the sampling methods used and the required analyses, the samples may be collected directly into the containers from the substrate or they may be returned, in bulk, to the bank or other sampling platfonn for processing and sample container allocation.